Protective fire alarm



Sept. 9, 1952 N Q TURNER 2,609,786

P-ROTECTIVE FIRE ALARM Filed June 25, 1950 INVENTOR NORBERT OLIVER TURNER in an inoperative position.

Patented Sept. 9, 1952 UNITED STATES PATENT OFFICE.

PROTECTIVE FIRE ALARM Norbert Oliver Turner, Toronto, Ontario, Canada Application June 23, 1950, Serial No. 169,867

6 Claims. 1

My invention relates to improvements in fire alarms of the mechanical type comprising an annunciator in the form of a bell and a striker motivated by an actuating mechanism including release means controlled by a fuse of metal having a low melting point.

The primary object of the invention is to provide an improved fire alarm of the character referred to comprising release means including an operating lever held in an operative position by means of a fusible strip of material. The fusible strip has a low melting point which renders it capable of readily melting in the presence of heat of an abnormal temperature such as that due to the presence of an outbreak of fire. The arrangement is such that should the fusible strip be melted by a condition of fire in the vicinity of the apparatus the operating lever frees the actuating mechanism in orderto set the striker in operation for raising an alarm.

A further and important aim of the invention is to produce a reliable and serviceable fire alarm of the kind described which is inexpensive to manufacture and which is admirably suitable for use in dwellings and other places. where an outbreak of fireis likely to occur. It is not intended that the invention shall be limited in its use since additional uses may be found for it and it may have as Wide an application as fairly comes within the scope of the invention.

A still further and salient object of the invention is to provide a fire alarm structure in which the release lever carries a fixed detent and in which a spring motor actuates a striker and includes a gear or other rotative element which is normally engaged by said detent to retain the spring motor against operation until an outbreak oi fire occurs of an intensity such as to melt the fusible strip by which the operating lever is held In one form of. the invention the operatin lever, when released by the fusible strip, is adapted to be vibrated by the engagement of the detent with teeth of a gear driven by the spring motor. A striker is carried by said lever in order to act on a bell for raising an alarm. The lever is resiliently pressed toward the gear as by a spring.

In a variant form of the invention there is an arrangement of resilient strikers carried by a gear or other rotary element and disposed to have wiping contact with depressing agents whereby they are caused to strike a bell When the gear is rotated.

With these and other objects in view the invention consists in the novel construction and arrangement of parts as disclosed in the accompanying drawing and described in the ensuing specification.

In the drawing, Fig. 1 is .a sectionized plan view of the invention taken substantially on the line l-l of Fig. 2.

Fig. 2 is a vertical sectional view of the invention.

Fig. 3 is a plan view similar to Fig. 1 but showing a variant form of the invention.

Fig. 4 is a fragmentary perspective view of the modified form of the invention showing how a striking element or hammer rides over a depressing agent for causing it to strike the bell.

Fig. 5 is a sectional detail taken on the line 5-5 of Fig. 1.

In carrying out my invention I'provide a suitable support which is shown by way of example as consisting of a base plate 6. Upon this base there is mounted a conventional form of spring motor comprising a main gear 1 journalled on a fixed spindle 8 and engaged with an idler gear 9 fixed on a spindle Ill. The main gear 1 is made rigid with a spring housing I I containing a spiral spring l2. In the present instance the inner end of the spring 12 is fixed, as at l3, to the stationary spindle 8, and the outer end thereof is fixed to the housing I l, as at M. The live spindle I0, which turns with the gear 9, may be supported in any approved manner as by the bearing 15, and is supplied with a key l6 by which it can be turned.

With this arrangement it will be manifest that the key l6 when turned in the proper direction will rotate the gears and thus wind the spring to store energy for an operative action in which the main gear reversely turns as a unit withthe housing ll.

At a side of the main gear 1 there is provided a lever I1 pivoted at l8 and fashioned with an integral pawl or detent 19 of a tapered shape for engaging the interdental spaces of the main gear with an impositive action. According to this arrangement the main gear can be turned by the key [6 in a direction to wind the spring. At the end of each turn of the key the main gearv can be held against retrograde movement by applying hand pressure on the lever to cause the pawl or detent l9 to engage in a space between adjacent teeth to lock this gear against movement.

ll fuse strip 20 of metal or comparable material is employed to retain the detent lever in its engaged position when the spring has been wound. This strip is attached in a suitable manner, as for instance by the pins 2! and 22. The pin 2i upstands from the base 6 and is engaged in a hole 23 provided in one end of the strip. The pin 22 upstands from the distal end of the lever and is engaged in a hole 2 3 provided in the other end of the strip. In this way the lever is positively locked in its engaged position, but is capable of being freed by the melting of the fuse strip, as in the case of a fire. Spring pressure, such as that exerted by the leaf spring 25 is utilized to press the lever toward the main gear in order tocausel the,

pawl or detent E9 to ride on the eeth of this gear when the lever is freed by the melting of the fuse strip. In this way the lever is induced v shaped member fastened on the fixed spindle 8.

Accordingly it will be manifest that the invention provides a serviceable and reliable fire alarm which can be placed in a room of a dwelling or otherwise located to sound an alarm in the event of a fire.

In the variant form of the invention illustrated in Figs. 3 and 4, the modification comprises the provision of one or more strikers on a'rotary element of the spring motor in lieu of the harnmer 26 previously described. Prefe ably said strikers are carried by the housing 2 i which ro tates concentrically within the bell 2i; Cue or a plurality of these strikers may be employed and each comprises a rod 23 radiallyprojecting from the side wall of the spring housing if! and rigid therewithv Fixed on the outer end of said rod is a resilient arm 29 which extends backwardly in a circumferential manner with regardto the direction in which said housing turns in the unwinding of the spring 552. On the free end of the arm 28; is-a spherical hammerhead closely adjacent to but out of contact with the skirt portion of the bell. In the path of travel of the hammer-head 3b is a depressing agent 3| shown as a fixed upright having opposite angular sides 32 meeting at a crest The heads 3i! ride over the uprights'ti in the rotation of the spring housing ll and therefore deliver a number of blows to the beli in each complete revolution of the, main gear.

Upon the occasion of a fire in the immediate vicinity of the alarm device the melting of the fuse strip 2%} releases the lever ll which permits the main gear to be turned together with the housing H by means of the spring l2. During rotation of the housing the individual hammerheads 38 approach the uprights 2i and are'forced back-wardly as they climb the adjacent inclined faces 32 thereof, whereupon they are freed abruptly as they ride over the "crests In this way they strike the hell with desirable force .in order to raise an alarm. The oppositely arranged faces 32 enable the hammer-heads to pass thereover in reverse direction as is required when the spring i2 is being wound.

The invention provides a cheap and reliable fire alarm, and it will be understood that such port, a circular bell thereon, a rotator mounted on said support concentrically within said bell,

a hammer having a flexible arm extending outwardly and circumferentially from said rotator and having a head carried by said arm and disposed in close proximity to the skirt portion of said bell, and an upright element on said support and in the path of travel of said head, said upright element having inclined contact faces meeting at a crest over which said head is caused to ride in order to strike said bell.

2. A protective fire alarm comprising a support, a bell thereon, a spring motor including a driven element rotatable about an axis concentrically of said bell, a resilient arm carried by said element and extending in a circumscribing manner about said element and within said bell, a strike head on the free end of said arm, and a depressing agent in the form of a fixed upright on said support and located interiorly of said bell, said upright having an angular face situated in the path of travel of said strike head whereby to depress the same to cause it to strike the bell when the strike head is moved past said angular face.

3.. A protective fire alarm comprising a support, a bell thereon, a spring motor including a driven element rotatable about an axis concentrically of said bell, resilient arms carried by said element in circumferentially spaced relation to extend in a circumscribing manner about said element and within said bell, strike heads on the distal ends of said. arms, and a plurality of circumierentially spaced depressing agents in the form of uprights fixed on said support in close proximity to the skirt portion of said bell, said uprights having angular faces disposed to be engaged by said heads to effect a depressing action.

4. In a fire alarm, a support, a bell thereon, a spring motor mounted on said support, said motor including a gear journalled concentrically of said bell, a strikerdevice including a striker operated by said motor to hit said bell, a lever pivoted on said support, means on said lever providing a tapered dog for interdental engagement with said gear, and a strip of fusible material locking said lever to said support with said dog engaged with said gear to prevent sounding of an alarm in the wound condition of the motor until the fuse strip is melted as by outbreak of a fire.

5. In a fire alarm, a support, a bell thereon, a spring motor mounted on said support, said motor including a gear .and a spring housing both mounted concentrically of said bell at the open side thereof, resilient striker arms'carried at the periphery of said housing and extending substantially circumferentially within the confines of said bell, heads on said striker arms, depressing agents in the form of uprights fixed on said support in close proximity to the skirt portion of said bell, said uprights having angular faces disposed to be engaged by said fheads during operation of said motor, a device retaining said motor inactive in the Wound condition of said spring, said device including an element movably supported on said support and held in interdental engagement with said gear .by a fusible strip.

6. In a fire alarm, a support, a bell thereon, a spring motor mounted on said support, said motor including a gear and a spring housing both mounted concentrically of said bell at the open side thereof, resilient striker arms carried at the periphery of said housing and extending substantially circumferentially within the confines of said bell, heads on said striker arms, depressing agents in the form of uprights fixed on said support in close proximity to the skirt portion or said bell, said uprights having angular faces disposed to be engaged by said heads during operation of said motor, a lever pivoted on said support and having a tapered dog, said dog having interdental engagement with said gear in an REFERENCES CITED UNITED STATES PATENTS Lambert July 6, 1937 

